Is there a map function in Ruby? [duplicate]

Question

I want to map values from a named list in Ruby. Is there an equivalent map function in Ruby? I have an array

letters = ['a', 'b', 'c', 'd']
capital = letters .map { l, l .capitalize] } 
puts capital

Answer 1

Yes, Ruby arrays have a .map method that you can call (https://ruby-doc.org/core-2.7.5/Array.html#method-i-map).

What you probably want is:

letters = ['a', 'b', 'c', 'd'] 
capitals = letters.map {|letter| letter.capitalize}

or you could also use the shorter form:

letters = ['a', 'b', 'c', 'd'] 
capitals = letters.map(&:capitalize)

or maybe even use the .upcase instead of .capitalize if all you need for the result is uppercase.